Zinc Metal Finish

Q: How many hours of salt spray resistance (ASTM B117) does your finish provide?

As a sacrificial anode coating, zinc naturally protects the base metal by corroding first. However, the overall hours to white/red rust depend heavily on the chromate conversion coating applied over the zinc layer. Generally, our Trivalent Clear provides up to 96 hours to white rust, while our high-build Yellow can exceed 120+ hours. If your application requires specific salt spray hours, specify it in your RFQ, and we will tailor the bath chemistry to meet it.

Zinc Metal Finish Specifications

Premature part failure is not an option. Whether your components are housed in a climate-controlled enclosure or exposed to corrosive outdoor elements, a generic coating won’t survive. At ShincoFab, we engineer your zinc metal finish by strictly controlling plating bath chemistry and current density to meet exact zinc plating thickness specifications and corrosion-resistance requirements.

Certified Industry Specifications

ASTM B633 zinc plating (Electrodeposited Coatings of Zinc on Iron and Steel) covering Types I, II, III, and V.
QQ-Z-325 (Federal Specification for Zinc Coating)
ISO 4042 (Electroplated Coating Systems for Fasteners)

Service Condition (SC) Thicknesses

To ensure your parts survive their intended operational environment without galling, flaking, or red rust, we hold precise micron thicknesses across all four standard service conditions.

SC1 (Mild) / 5µm Minimum Thickness: Engineered for indoor applications. Parts subject to minimum wear and negligible condensation.
SC2 (Moderate) / 8µm Minimum Thickness: Designed for dry indoor environments with occasional exposure to condensation or mild moisture.
SC3 (Severe) / 13µm Minimum Thickness: Specified for outdoor applications subject to infrequent rain and moderate corrosive elements.
SC4 (Very Severe) / 25µm Minimum Thickness: Built for harsh industrial environments, heavy outdoor exposure, and applications requiring high abrasion resistance.

Chromate Conversion Options and Compliance

When specifying custom zinc plating finishes and colors, the chromate dictates both function and regulatory compliance. Whether your specs require an environmentally friendly zinc plating process (Trivalent) or legacy Hexavalent formulations, ShincoFab matches the exact chemical conversion coating to your blueprint.

Clear / Blue Chromate (Trivalent)

Compliance: 100% RoHS compliant zinc plating and REACH certified.
Functional Profile: Provides a bright, metallic silver-blue appearance with mild to moderate corrosion protection.
Best For: Fasteners, brackets, and interior hardware requiring aesthetic uniformity and environmental compliance.

Yellow / Iridescent Chromate

Compliance Warning: Available in both modern Trivalent (RoHS Compliant) and legacy Hexavalent (Non-RoHS) formulations for older military/automotive specs. Please specify your compliance requirement on your RFQ.
Functional Profile: Offers exceptionally high bare-metal corrosion resistance.
Engineering Note: Do not specify yellow chromate if the part requires subsequent painting or powder coating. It acts as a poor primer base and will cause adhesion failures. Use Clear/Blue for pre-paint applications.

Black Chromate (Trivalent)

Compliance: 100% RoHS & REACH Compliant.
Functional Profile: Delivers a uniform matte to semi-bright black finish. Formulated specifically to absorb light and prevent glare.
Best For: Optical equipment, zinc plating for defense and military hardware, and under-the-hood components requiring highly durable zinc plating for automotive applications.

Production Capabilities Tailored to Part Geometry

We don’t treat precision sheet metal chassis the same way we treat a bucket of fasteners. To guarantee uniform plating thickness without mechanical damage, we route your parts through dedicated rack or barrel lines based on their geometry, weight, and volume.

Rack Plating for Complex Geometries

Best For: Sensitive sheet metal enclosures, large brackets, and components with complex bends or critical threaded holes.
The Advantage: Parts are individually fixtured to ensure optimal current distribution and absolutely zero part-on-part mechanical damage (no scratching, galling, or deformation).
Capacity: Accommodating oversized part dimensions up to 120″ L x 30″ W x 60″ D with hoist capacities up to 1,200 lbs.

Barrel Plating for High Volume

Best For: Fasteners, nuts, washers, and small, robust stamped brackets.
The Advantage: Engineered for massive throughput. Delivers consistent, uniform micron thickness across runs of 10,000 to 50,000+ pieces.
Capacity: Highly economical processing with optimized tumbling speeds to prevent nesting of flat parts.

Approved Substrate Materials

Proper surface activation is critical for adhesion. Our pre-treatment lines are chemically configured to process a strict range of base metals.

Carbon Steel (Cold Rolled and Hot Rolled)
Low-Alloy Steel
Cast Iron
Copper and Brass

Process Control for Zero Coating Failures

A perfectly fabricated sheet metal part can be instantly ruined by poor plating chemistry. We don’t rely on visual inspections; we rely on metallurgy, strict pre-treatment protocols, and in-house lab validation to guarantee zero flaking and prevent catastrophic part failure.

Hydrogen Embrittlement Relief Zinc Plating

The Risk: High-tensile steel is highly susceptible to hydrogen embrittlement during the electrodeposition process, leading to delayed, catastrophic cracking under stress.
Our Process: For components with a hardness of 31 HRC or higher, we mandate strict, time-critical post-plate baking cycles. Parts are transferred directly from the plating line to our calibrated ovens to safely outgas trapped hydrogen, ensuring full structural integrity.

Surface Preparation for Plating

The Process: Anti-rust metal plating only sticks to absolutely clean metal. All batches undergo rigorous alkaline cleaning and specialized acid pickling.
The Result: Complete removal of fabrication oils, scale, and oxides, guaranteeing 100% molecular adhesion and zero risk of blistering or flaking in the field.

In-House Lab Verification

Thickness Control: On-site X-Ray Fluorescence (XRF) equipment verifies exact micron thickness to ensure strict compliance with your specified SC tolerances.
Corrosion Testing: Validating our corrosion resistance zinc plating through routine salt spray testing (per ASTM B117) ensures your parts meet the required hours to white and red rust.

Predictable Turnarounds and Complete Documentation

Engineering approves the spec, but procurement needs the parts on the dock. Every delivery must arrive strictly on time and fully documented. A missing certificate of compliance or a delayed shipment can shut down your entire assembly line. We built our production schedules and QA reporting to integrate seamlessly into your JIT manufacturing ecosystem.

Reliable Turnaround Times

Standard Lead Time: 3 to 5 business days for standard rack and barrel zinc plating.
Expedited Services: 24-to-48-hour emergency processing available to prevent line-down situations. (AOG/Urgent routing supported).

Logistics & Inventory Management

JIT & KanBan Support: We support Just-In-Time delivery schedules and KanBan bin replenishment programs to reduce your warehousing costs.
Local Fleet Transit: For regional partners, we offer dedicated pickup and delivery routes to eliminate third-party freight delays and hidden shipping damages.

Audit-Ready Documentation

Certificates of Compliance (CoC): A signed CoC verifying thickness, SC level, and RoHS/REACH compliance is included with every shipment. No chasing paperwork.
Advanced Quality Planning: Full support for PPAP (Production Part Approval Process, Levels 1-5), Control Plans, and FAI (First Article Inspection) reports for automotive, military, and strict OEM supply chains.

Frequently Asked Questions

In the world of industrial metal coatings, a fraction of a micron can be the difference between a perfect assembly and a scrapped part. We don’t just dip parts in a tank; we proactively engineer potential failures out of the process. From calculating pre-plate thread allowances to mitigating structural risks, review the technical answers below—or submit your blueprint for a direct consultation.

Will zinc plating alter the dimensions of my tapped holes and internal threads?

Yes, but we plan for it. Zinc plating adds material (typically 5µm to 13µm depending on the SC level). This build-up is magnified on threaded surfaces. If your parts have tight-tolerance tapped holes, please note this on your RFQ. We use specific bath controls and can recommend the proper pre-plate thread allowances to prevent thread binding.

Can you plate specific areas of my part and mask others?

Absolutely. We offer precision masking services for ground points, specific threaded holes, or mating surfaces where bare metal is required. We use custom silicone plugs and high-temperature masking tapes to ensure sharp transition lines and zero plating bleed.

How many hours of salt spray resistance (ASTM B117) does your finish provide?

As a sacrificial anode coating, zinc naturally protects the base metal by corroding first. However, the overall hours to white/red rust depend heavily on the chromate conversion coating applied over the zinc layer. Generally, our Trivalent Clear provides up to 96 hours to white rust, while our high-build Yellow can exceed 120+ hours. If your application requires specific salt spray hours, specify it in your RFQ, and we will tailor the bath chemistry to meet it.

Do you provide hydrogen embrittlement relief baking certificates?

Yes. For high-tensile fasteners and formed sheet metal parts (hardness >31 HRC), we mandate post-plate baking within hours of electroplating. A documented baking certificate is included with your Certificate of Compliance (CoC) upon delivery.

Request a Zinc Plating Quote (24-Hour Turnaround)

Skip the sales pitch. Upload your CAD models and technical specifications below. Our finishing engineers will review your geometry, calculate surface area requirements, and provide a definitive quote and lead time within 1 business day.

Zinc Metal Finish